1. Technical Field
This application generally relates to data movement, such as data copying and/or relocation and techniques for controlling such operations.
2. Description of Related Art
Computer systems may include different resources used by one or more host processors. Resources and host processors in a computer system may be interconnected by one or more communication connections. These resources may include, for example, data storage devices such as those included in the data storage systems manufactured by EMC Corporation. These data storage systems may be coupled to one or more host processors and provide storage services to each host processor. Multiple data storage systems from one or more different vendors may be connected and may provide common data storage for one or more host processors in a computer system.
A host processor may perform a variety of data processing tasks and operations using the data storage system. For example, a host processor may perform basic system I/O operations in connection with data requests, such as data read and write operations.
Host processor systems may store and retrieve data using a storage system containing a plurality of host interface units, disk drives, and disk interface units. Such storage systems are provided, for example, by EMC Corporation of Hopkinton, Mass. The host systems access the storage system through a plurality of channels provided therewith. Host systems provide data and access control information through the channels to the storage system and the storage system provides data to the host systems also through the channels. The host systems do not address the disk drives of the storage system directly, but rather, access what appears to the host systems as a plurality of logical disk units, logical devices, or logical volumes (LVs). The logical disk units may or may not correspond to the actual disk drives. Allowing multiple host systems to access the storage system allows the host systems to share data stored therein.
In connection with a data storage system, and more generally any suitable system such as a computer system, it may be desirable and/or necessary to perform a data movement operation for any one of a variety of different purposes. It may be desirable to utilize techniques for controlling performance of such data movement operations to thereby limit resources utilized so as to limit adverse effects upon other tasks. For example, in a data storage system, it may be desirable to use such techniques to balance performing data movement operations with other operations such as received I/O requests or data operations received from hosts storing and retrieving data stored on the data storage system.